Apparatus for handling materials



March 21, 1944. F, KEMPER APPARATUS FOR HANDLING MATERIALS Filed Sept.17, 1940 Patented Mar. 21, 1944 7 UNITED STATES PATENT OFFICE APPARATUSFOR HANDLING MATERIALS Maxwell F. Kemper, Los Angeles, Calif.Application September 17, 1940, Serial No. 357,120

10 Claims- (Cl. 302-57) My invention relates principally to thepneumatic conveying of discrete solid particles in a wet, dry orsemi-fluid state, such as grain, sand, mixed materials of varying sizes,cement or mixed concrete in its wet semi-fluid or plastic state readyfor placing in final position.

The object of the invention is to provide means for improving pneumaticconveyance of such materials so as to prevent segregation orclassification of mixed materials into different types or sizes duringthe blowing operation, to prevent discharge in slugs or wads separatedby air pockets, and to reduce the volume of air required with consequentreduction in pressure equipment cost, and power consumption.

The invention resides primarily in an air-control valve for controllingthe supply of air into a discharge throat at the lower end of amaterials supply hopper, which valve opens by movement into or towardone end of said throat and has a pointed end directed toward said throatso as to penetrate readily into wet mixed concrete or other loose solidparticles. The hopper is a pressure chamber sealed at its top, and thematerials are discharged from the opposite end of said throat. Theinvention resides also in the particular shape of said valve whichapproximates turnip-shape whereby to distribute the high pressure airevenly behind or through the cement bodies, or other bodies of solidparticles, which are to be picked up by the air stream and conveyed. Therear portion of the valve is generally a part of a sphere beingapproximately or somewhat more than a half-sphere, while the valve pointis reversely curved to elongate the valve beyond the normal limits ofthe sphere, to yield a streamlined structure producing streamlinedmovement of the air. The invention also resides in an elongatedhorizontal throat at the bottom or discharge end of said hopper intowhich throat the hopper feeds, in combination with a compression chamberin which said valve works, whose inner walls approach in shape aparabola having its axis alined with the axis of the throat. Theinvention also includes the use of a conical bot-.

tom for the hopper, said bottom feeding to said throat, its conicalshape insuring proper gravity feed of the materials to the throat.

In the pneumatic conveying of particles of mixed sizes, and of wet mixedconcrete in particular,1 have found that with the ordinary types ofapparatus the concrete is picked up in slugs with air pocketstherebetween containing lighter materials separating the slugs, with theresult that the concrete is conveyed in slugs and dis-- charged"shot-gun fashion. This operation causes a segregation of the largerparticles or aggregate from the smaller sand particles, water andcement. This classifying action, especially when thin walls are beingformed, shows coarse rock pocket-s interspersed in the main body offiner cement materials when the forms are removed. Such unevenness isobjectionable from all standpoints, such as strength, penetration andappearance. These objections are overcome by the present arrangement ofdischarge throat, compression chamber receiving the valve, and thereversely curved pointed valve.

r In the accompanying drawing wherein the invention is illustrated incertain embodiments,

I Fig. '1 is a vertical section showing the discharge throat and valveas employed on the lower end of the conical bottom of a materials hopperor pressure chamber;

Fig. 2 is a cross section from line 2-2 of Fig. 1.

Fig. 3 is a cross sectional detail taken on line 33 of Fig. 1.

The lower end H of the conical bottom of a sealed pressure chamberadapted to be filled with mixed wet concrete or other materialscomprising solid particles supplied through a scalable gate at the top,is shown as being securely joined to an elongated horizontal throat ill.The top of throat I0 is flared out in conical formation at I to join thehopper bottom I-I, this throat top F being circular'in cross section atthe cross-section line 22 as shown in Fig. 2. Both extreme ends ofthroat l0 beyond the inlet, portions of the flared section F arecircular in cross section.

' Thus, the circular discharge end D of throat It) may be joined'to acylindrical discharge pipe P and the circular air inlet end A of throatl0 may be joined to a circular compression chamber member Cwhich'receives and provides a seat for the air-control valve V. i

, The compression chamber 0 is a chamber which first receives highpressure air admitted by valve V. The curves of its inner walls llclosely approximate parabolas. While this form is preferred, ellipticalcurves may be used with a fair degree of success; less satisfactorycurves would be 'hyperbolas, semi-circles and the like 'to produce otherforms of concave chambers. The axis of these walls alines with the axisof the throat l0, and the circle at the extreme outer edge coincideswith that of the adjacent inner wall of throat Ill. The rear of thesewalls ll adjacent the apex is formed into a seat for the spherical rearportionl-2 of the valve-V.

The rear and middle portions of the valve V are generally spherical inshape except as the rear portion is flared away to join the valve stemI3; or it may be said that the rear portion constitutes a half-sphere orsomewhat more than a halfsphere except for the connection with valvestem I3. From the middle portion the valve is reversely curved at M andextends forward to a point or tip [5 which may be blunt at its. extremeend.

This curvature is such that it makes the length of the entire valve,exclusive of the valve stem, slightly less than or approximately twicethe diameter of the full sphere generally represented by the rearportion 12 of the valve. This contour is stream-line and may begenerally termed of turnip-shape.

The pointed forward end ll: of the valve V facilitates its forwardmovement into a body of soft concrete or other body of solid particlesfeeding down from the hopper H. When the valve V is moved forward fromits seat on compression chamber member C, it admits high pressure air tosaid chamber C and throat In from a chamber in a valve carrier Ksupplied by an air line 22. Carrier K is secured to member C by bolts23, and valve V is positioned by the mounting of stem IS in a boss 24projecting into chamber 20, the valve stem being packed in said carrierand boss at 2-5.

Valve V is normally held closed by a sufi'iciently heavy spring 28around valve stem l3. It is openedthrough a lever 28 f-ulcrumed at 29 ona positioning link 30 pivoted at 3! on the body of carrier K, lever 28being pivotally connected at 32 with the outer end of said valve stem[3. Movement of the lever handle 28 to the left as desired opens valve Vby movement to the right. In operating the device, the hopper H willhave been filled with concrete or other substance to be pneumaticallyconveyed and will have had its filling opening at the top sealedsubstantially air tight. The tapered or conical bottom. H of the hopperand the correspondingly flared or tapered section F will insure asufficiently even feedof the materials into the throat Ill which isfully cylindrical at its air inlet end A and at its discharge end D, andis approximately semi-cylindrical in the lower, half of its middleportion, the sides of thesection F above said middleportion slopinguniformly down to join the upper portion of the semi-cylindrical portionas seen in Figs. 2 and 3. Forward of the middle portion of throat I0,the sidewalls are rounded away as shown at R to offer the leastresistance to the down flow of the concrete and to the discharge of thesame from the dis-charge end D-of throat l0 into discharge pipe P.

At the rear or air inlet end A of throat I 0, the, cylindrical contourofthe end A is maintained as much as possible so that the main boretends to extend straight through alongthe axis of throat II) to causethe air stream to be directed toward the discharge D. Thus, where thesloping walls of section F join the cylin-' drical section A of throatID a sharp sloping shoulder results as indicated at S.

By virtue of the parti-spherical contour of the rear portion of valve Vtogether with the reversely curved portion I4 of the point l5 thereof,and the generally parabolic form of the comression chamber walls II, theair stream admitted past valve V is uniformly distributed over thecircular cross-sectional area of throat Ii) behind the descending bodyof concrete, whence it uniformly mixes with the concrete and feeds itforward without apparent segregation or classification of particles ofdifferent sizes and condition. This stream-lined air flow, together withthe gravity feed from the conical hopper, causes a continuous uniformconveying of the concrete through an elongated extension of dischargepipe P to the point of deposit, and results in a uniform deposit withoutrock pockets and segregated fine material, water and the like. At thesame time, the air volume required has been found to be reduced by asmuch as The term turnip-shape is here used to indicate the stream-linedor spheroidal contour of the valve V with its elongated reversely-curvedpointed extension 15, and the term parabolic" refers to the form ofconcavity shown and described as the shape of wall ll of the compressionchamber C. Modifications to produce the same or like results will occurto those skilled in the art.

I claim:

1. Apparatus for the pneumatic conveying of loose particles comprisinga' horizontal throat, means to feed particles into said throat laterallythereof, discharge means in line with aid throat to conduct particlesaway from said throat, a chamber aligned with said throat and having avalve seat at its end remote from said throat, a pointed valve Withinsaid chamber adapted to seat on said seat and movable axially of saidchamber, said valve having a projected area within the chamber normal tothe chamber axis greater than the area of the opening in the valve seat,and means for supplying air past said valve. 1

2. Apparatus for pneumatically conveying loose materials comprising anelongated throat having an air receiving end, a discharge end and amaterials supply inlet, a concavity alined with the axisof saidthroatand ends and having a valve seat whose axis alines with said axis,a pointed spheroidal valve alined with said axis and movable alongsaidaxis from said seat toward said throat, and an air supply to saidvalve seat to supply air past said valve for discharging'said materialsthrough said discharge end.

3. Apparatus according to claim 2 wherein said I concavity approximatesparabolic shape. 50

4. Apparatus according to claim 1 wherein the rear portion of the valveadjacent said seat ispar-ti-spherical and the forward portion of thevalve is reversely curved and extended to a point directed toward saidthroat.

5. Apparatusaccording to claim 1 wherein the rear portion or" the valveadjacent said seat is parti-spherical and the forward portion of thevalve is reversely curved and extended to a point along said axis, andthe chamber is concave with a curvature which approximates a parabola.

' 6. A; pneumatic feed comprising a discharge throat, a curved wallchamber co-axial-ly alined and communicating with said throat and having7 a valve seat and a co-axiall'y alined turnipshaped valve seating onthe low pressure side of said valve seat'and pointed into said throat"to distribute air evenly thereto.

7. Apparatus for the pneumatic conveying of loose particles comprising athreat; means to feed particles into said throat; discharge means toconduct particles away from said throat; a

.chamber in communication with said throat; an opening in said chamberfor admitting air to said chamber; and a body within said chamber havinga projected area normal to the axis; of

said opening greater than the area of the opening; said body beingmovable toward and away from said opening to thereby control the flow ofair'into said chamber.

8. Apparatus for the pneumatic conveying of an aggregate of looseparticles of different sizes and weights, comprising; means forming athroat; means to feed said aggregate laterally into said throat;discharge means connected to one end of said throat to conduct theaggregate away from the throat; a chamber communicating with the otherend of said throat; an opening in said chamber for admitting air to thechamher, the walls of said chamber diverging in a direction away fromsaid opening and toward the throat; and a body within said chamber, thesurface of said body diverging from the walls of the chamber and towardthe throat, the walls of said chamber and the surface of said bodycooperating to define a passage surrounding said body graduallyincreasing in cross section from said Opening toward said throat,whereby air flowing through said passage is caused to impinge upon thatsurface of the body of aggregate facing said passage with asubstantially uniform velocity, to move said aggregate without causingsegregation of particles of different sizes and weights in theaggregate.

9. A valve for the pneumatic conveying of loose particles comprising achamber having an opening at one end thereof for the admission of air,the walls of said chamber being gradually divergent from said opening, abody within said chamber having a projected area normal to the axis ofsaid opening larger than the area of said opening, said body being of agenerall spheroidal shape, the walls of the chamber and the surface ofsaid body defining an annular passage of gradually increasing crosssection.

10. Apparatus for the pneumatic conveying of an aggregate of looseparticle of different sizes and weights, comprising; means forming athroat; means to feed said aggregate laterally into said throat;discharge means communicating with one end of said throat to conduct theaggregate away from said throat; conduit means communicating with theother end of the throat; a member in said conduit having a surface di-,verging from the wall of the conduit toward the throat, said member andsaid conduit cooperating to form a passage gradually increasing in crosssection in the direction of air flow therethrough, said passage beingpositioned adjacent said throat and causing the air passing therethroughto impinge upon the surface of the body of aggregate between thedischarge end of said passage and said throat with a substantiallyuniform velocity, to move said aggregate without causing the segregationof particles of different sizes and weights in the aggregate.

M. F. KEMPER.

